MWC is a relaxacon — the relaxacon — which has been run each year since 1949 by the CFG on the last full weekend in June. (The first few Midwestcons were known as the Nth Indian Lake Convention after the site at which they were held.)

Midwestcon has long been a destination for smofs, and you are apt to see many more ex-Worldconchairs there than at almost any other con short of Worldcon itself. And woe betide the Worldcon bid that doesn't throw a bid party at Midwestcon.

A weekend affair in the early summer, so far held in Ohio… originally at Beatley's on Indian Lake, later at Bellefontaine, and finally at a giant motel in Cincinnati. Don Ford and Doc Barrett covered themselves with much egoboo by organizing this gathering at which program is kept to a minimum and fangabbing runs rife. It was forced to move its site to Bellefontaine after a rather crude affair in 1954 (the blame for which was laid on the 7th Fandomites, with what justice your Herodotus has been unable to determine), then to Cincinnati when the gathering became too big for Bellfontaine's facilities. It has thus far been an annual event to be sought by all knowing fans.

from Fancyclopedia 2 Supplement ca. 1960:
The locations were out of order. The first was in Bellefontaine, in 1950; when it became plain that it was to become more than a small gathering of friends in Doc Barrett's living room, larger facilities were sought and found at Beatley's on Indian Lake. In 1954 the convention moved to Bellefontaine, where the door was broken in 1955. in 1956 — and up to date, — they've been at the North Plaza Motel in Cincinnati.